The present disclosure relates to an orifice structure and, more particularly, to a self-cooled orifice structure of a gas turbine engine.
Gas turbine engines, such as those that power modern commercial and military aircraft, include a fan section to propel the aircraft, a compressor section to pressurize a supply of air from the fan section, a combustor section to burn a hydrocarbon fuel in the presence of the pressurized air, and a turbine section to extract energy from the resultant combustion gases and thereby generate thrust.
The combustor section typically includes a wall assembly having an outer shell lined with heat shields that are often referred to as floatwall panels. Together, the panels define a combustion chamber. A plurality of orifices, such as dilution holes, are generally spaced circumferentially about the wall assembly and flow dilution air from a cooling plenum and into the combustion chamber to improve emissions, and reduce and control the temperature profile of combustion gases at the combustor outlet to protect the turbine section from overheating.
The orifices are generally defined by a grommet that extends between the heat shield panel and supporting shell with a cooling cavity defined therebetween. Improvements to the cooling of structures surrounding the orifices is desirable.